Serum ammonia test procedure

The serum ammonia test measures the level of ammonia in the blood, helping diagnose conditions like liver disease or urea cycle disorders.

Serum ammonia test procedure steps for ammonia test.

Confirm the patient’s identity using two identifiers (e.g., name and date of birth).
Ammonia-free heparinized collection tube (usually green-top or lavender-top tube for EDTA).
Apply a tourniquet to the upper arm to make the vein more prominent. Avoid prolonged use, as it can affect ammonia levels.
Disinfect the venipuncture site with an alcohol swab, allowing it to dry.
Use a sterile needle and syringe or vacuum system to collect the blood sample. Avoid hemolysis, as it can falsely elevate ammonia levels.
After collecting the sample, withdraw the needle, apply pressure to the puncture site with gauze, and secure with adhesive tape.
Transfer sample Immediately otherwise place the sample tube in an ice slurry to prevent degradation of ammonia.

Lab Analysis steps

Add 200 µL of R1 reagent into the reaction cuvette or test tube.
Add 5 µL of the sample to R1.
Mix gently and incubate for 2–5 minutes at 37°C to allow initial stabilization.
Add 50 µL of R2 reagent to the mixture. Mix again and incubate according to the kit instructions (e.g., 5–10 minutes at 37°C).
Measure absorbance at the specified wavelength (e.g., 340 nm).

Ensure the patient avoids strenuous exercise before the test, as it can increase ammonia levels.
Avoid smoking or alcohol consumption prior to the test, as they can also interfere with results.
Delay testing if the patient has undergone recent physical trauma or surgery, as these conditions can affect ammonia levels.